Paeds · fetal-neonatal-and-perinatal
Neonatal jaundice: unconjugated hyperbilirubinaemia
Also known as Neonatal jaundice · Unconjugated hyperbilirubinaemia · Neonatal hyperbilirubinaemia · Physiological jaundice · Breast milk jaundice · Kernicterus
Fellowship guide to neonatal unconjugated hyperbilirubinaemia: bilirubin metabolism and pathophysiology, physiological versus pathological jaundice, hour-specific risk assessment using the Bhutani nomogram, phototherapy and exchange transfusion thresholds from the 2022 AAP guideline, haemolytic causes including ABO and Rh incompatibility and G6PD deficiency, breastfeeding jaundice, acute bilirubin encephalopathy and kernicterus prevention, and regional guideline differences.
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Target exams
Red flags
- Jaundice within the first 24 hours of life — always pathological, requires urgent TSB
- Total serum bilirubin at or above the exchange transfusion threshold for age
- Rapid rate of rise exceeding 85 micromol per litre per day or 5 mg per dL per day
- Acute bilirubin encephalopathy: lethargy, poor feeding, high-pitched cry, hypertonia, arching, or seizures
- Jaundice in a preterm infant less than 35 weeks gestation — lower thresholds apply
- Pale stools or dark urine suggesting conjugated hyperbilirubinaemia (biliary atresia)
- Family history of G6PD deficiency, previous sibling requiring exchange transfusion, or kernicterus
Life stages
Care settings
Clinical exam formats
Board mappings
- Distinguishes physiological from pathological neonatal jaundice
- Uses the hour-specific bilirubin nomogram for risk stratification
- Identifies jaundice within the first 24 hours as always pathological
- Justifies phototherapy and exchange transfusion decisions using 2022 AAP thresholds
- Interprets haemolytic workup including DAT, G6PD assay, and peripheral film
- Manages acute bilirubin encephalopathy and prevents kernicterus
- Hour-specific bilirubin plotting and treatment threshold interpretation
- Distinguishing breast milk jaundice from breastfeeding jaundice
- Recognising and managing G6PD deficiency-related hyperbilirubinaemia
- Assessment of the jaundiced neonate on the postnatal ward
- Counselling parents about phototherapy and the safety of continued breastfeeding
- Identifying conjugated hyperbilirubinaemia and urgent referral for biliary atresia
- Physiology of neonatal bilirubin metabolism and why jaundice is common
- Risk factors for severe hyperbilirubinaemia and kernicterus prevention
- Phototherapy and exchange transfusion management
- Pathophysiology of bilirubin-induced neurotoxicity
- Phototherapy and exchange transfusion thresholds
- Haemolytic causes: ABO, Rh, G6PD, hereditary spherocytosis
- Examination of the jaundiced neonate including cephalocaudal progression
- Communication of the management plan for a jaundiced newborn
- Recognition of acute bilirubin encephalopathy
- Application of the 2022 AAP hyperbilirubinemia guideline thresholds
- Risk factor assessment using the ESC or equivalent tool
- Phototherapy delivery and monitoring of response
- Systematic assessment of the jaundiced neonate
- Phototherapy initiation and escalation decisions
- Counselling families about breastfeeding and jaundice
- Canadian Paediatric Society approach to neonatal hyperbilirubinaemia
- Universal bilirubin screening and follow-up planning
- Identifying infants at risk of readmission
Overview & Definition
Neonatal jaundice, characterised by a yellow discolouration of the skin and sclerae from elevated bilirubin, is the single most common clinical problem in the newborn period, visible in approximately 60 per cent of term and 80 per cent of preterm infants. Unconjugated hyperbilirubinaemia accounts for the overwhelming majority of cases, arising from an imbalance between bilirubin production and hepatic clearance of this lipid-soluble heme degradation product. While most jaundice is benign and self-limiting, the potential for unconjugated bilirubin to cross the blood-brain barrier and cause irreversible neurological damage makes systematic assessment and risk stratification essential in every newborn. [3]
The clinical task is not merely to detect jaundice but to distinguish the common, benign physiological pattern from the minority of infants whose bilirubin will rise to dangerous levels. The key conceptual framework is that bilirubin toxicity is a function of both the total serum bilirubin concentration and the infant's vulnerability, which is amplified by prematurity, illness, haemolysis, hypoalbuminaemia, and acidosis. The goal of management is to prevent bilirubin from reaching levels at which acute bilirubin encephalopathy and its chronic sequela, kernicterus, can occur. [4]
The 2022 American Academy of Pediatrics guideline revision superseded the 2004 guideline with updated, gestational-age-specific phototherapy and exchange transfusion thresholds, revised risk factor definitions, and an increased emphasis on universal predischarge bilirubin screening with structured follow-up. Despite these advances, kernicterus remains a persistent, largely preventable cause of devastating neurological disability, and cases continue to occur due to failures in recognition, escalation, and follow-up. [2]
References9ShowHide
- [1]Bhutani VK Predictive ability of a predischarge hour-specific serum bilirubin for subsequent significant hyperbilirubinemia in healthy term and near-term newborns. Pediatrics, 1999.PMID 9917432
- [2]Kemper AR Clinical Practice Guideline Revision: Management of Hyperbilirubinemia in the Newborn Infant 35 or More Weeks of Gestation. Pediatrics, 2022.PMID 35927462
- [3]American Academy of Pediatrics Subcommittee on Hyperbilirubinemia Management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation. Pediatrics, 2004.PMID 15231951
- [4]Watchko JF Bilirubin-induced neurologic damage--mechanisms and management approaches. N Engl J Med, 2013.PMID 24256380
- [5]Watchko JF Bilirubin-Induced Neurotoxicity in the Preterm Neonate. Clin Perinatol, 2016.PMID 27235209
- [6]Maisels MJ An approach to the management of hyperbilirubinemia in the preterm infant less than 35 weeks of gestation. J Perinatol, 2012.PMID 22678141
- [7]Maisels MJ The natural history of jaundice in predominantly breastfed infants. Pediatrics, 2014.PMID 25049352
- [8]Newman TB Numbers needed to treat with phototherapy according to American Academy of Pediatrics guidelines. Pediatrics, 2009.PMID 19403502
- [9]Kaplan M Glucose-6-phosphate dehydrogenase deficiency and severe neonatal hyperbilirubinemia: a complexity of interactions between genes and environment. Semin Fetal Neonatal Med, 2010.PMID 19942489